Submitted to: International Entomophagous Insect Workshop
Publication Type: Abstract Only
Publication Acceptance Date: August 10, 2003
Publication Date: September 1, 2003
Citation: Pfannenstiel, R.S. 2003. Visually partitioning nocturnal and diurnal predation of lepidopteran eggs: lessons in the determination of key predators. International Entomophagous Insect Workshop.
Studies of predators (and predation) have focused largely on field studies of predator populations in certain crops and laboratory studies of predators observed in the field crops; relatively few have attempted to accurately document the predators responsible for mortality of particular pests in the field. The studies that have been conducted have used a variety of techniques including radio-isotopes to label prey, visual observation, and molecular techniques. In many cases these studies have resulted in small samples sizes and/or there are biases associated with these techniques that have not been adequately addressed. I conducted studies to more carefully describe the guild of predators that feed on eggs of lepidopteran pests of field crops, particularly Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) using visual observation. A primary focus of these studies was to partition diel patterns of predation and more accurately characterize nocturnal predation. Visual observations on predation of lepidopteran eggs were conducted in 1993 and 1994 in corn and soybean grown in Kentucky and from 2001 to 2003 in cotton, corn and soybean grown in South Texas. Results were compared to those from studies using other techniques. In both locations predator taxa, primarily nocturnal, were observed that had previously been unknown or underestimated in their importance as predators of lepidopteran eggs. The wandering spiders and the Phalangidae are two examples of important predators of eggs that have been typically unrecognized. Several diurnal predators that have been studied extensively appeared to be less important than previously believed. Predator complexes will be described and compared to those observed in other studies and the implications for biological control of lepidopteran pests discussed.